Abstract: For investigating microstructure and deposition mechanism of the low temperature isotropic pyrocarbon(LTIC), LTIC was prepared by a steady-state fluidized bed chemical vapor deposition experiments at different deposition temperatures with propane as carbon source of different volume fractions. Microstructure of the LTIC obtained at different deposition conditions was characterized using SEM and TEM. The results show that the LTIC obtained at different deposition conditions is composed of globular-like granular and laminar carbon structure. Increasing the deposition temperature is propitious to decrease the nucleation barrier forming pyrocarbon in vapor, which causes the quantity of globular-like particles with a smaller diameter increasing and the texture of the carbon layer around carbon black particles inside globular-like particles decreasing gradually. With increasing the volume fraction of propane, pyrocarbon deposition process is mainly dominated by surficial growth mechanism, and transforms to the gaseous nucleation mechanism. The globular-like particle morphology in obtained LTIC is more obviously and laminar carbon structure gradually decreases and even disappear completely.